Did you get both cylinders filled today? Does the indicator now show fully green?

Based on your previous post I think there is some confusion on the function of the pointer and the sight glass.
The pointer should be pointed at only one cylinder or the other and never in the center. When you point the indicator at one cylinder it does two things.

The pointer selects which cylinder the indicator window is monitoring.

The pointer tells you which cylinder is empty when you find the window red.

Also the window should always be full red or full green, never half and half. If the window goes only half way it is sticking and the regulator should be replaced.

Here's an easy test to verify the auto changeover functionality and it takes less than 10 minutes.

Start with both cylinders full and turned on.

Make sure the pointer is pointed at only one cylinder.

Go inside and light the oven at 350 degrees or put on a pot of water to boil.

Leave the burner or oven on and go back outside.

Turn off the cylinder that the pointer is pointed at to simulate running out of propane.

Observe the window, in a few minutes it should change from green to fully red meaning the cylinder is empty.

Do not move the pointer, just go back inside the trailer and check that the flame is still burning.

If it's still burning then you know your auto switchover regulator is working.

Now go outside and move the pointer over to the other cylinder.

The window should go from red to green.

This shows you which cylinder you are now drawing propane from.

Now to see if the regulator works in the opposite direction.

Turn on the first cylinder and turn off the second cylinder.

After a few minutes the indicator should once again turn red.

Go inside the trailer and observe the flame.

If the flame stays lit you know know the regulator will successfully auto switch in both directions.

Turn off the flame or oven.

Go outside and restore the pointer to the first cylinder and turn on both cylinder valves.

Now that you know the regulator will auto switch you have a decision to make. Which method that you read on here are you going to use.

Point at one cylinder. Leave the other cylinder turned off. Wait until you find out the cylinder is empty because the stove or furnace stops. This method could cause you to go out in the dead of night to turn on the other cylinder.

Check the indicator every evening or every other evening to see if it's red. If the window is red flip the pointer to the other cylinder and turn off the now empty cylinder. Go about your evening.

In the morning disconnect the now empty cylinder and get it filled. Then put the cylinder back on the trailer and depending on your method above either (method 1) Leave the cylinder off, or (Method 2) turn the cylinder on.

My setup has a auto changeover valve with a red/green indicator to show empty or not. When one tank goes empty the level indicator turns red and the valve automatically switches over to the full tank. I periodically check the tank indicator to see if it's red. If I see it's red then I turn the valve lever towards the full tank, turn off the empty tank, have it filled, re-install and turn it on.

My appliances never run out of propane unless by some fluke I run both tanks empty before getting a fill.

Yup, my LP switch turns on the right side tank when pointed to the right and the left side when pointed to the left. I believe middle is the off position.

It is true that automatic change over valves eliminates switching tanks on a cold rainy night. However, it is not of much help when it is cold and rainy and you discover it had switched over some time back and now both tanks are empty.